The proposed projects will examine the normal development of the nonhuman primate preimplantation embryo. Building on an established system for the in vitro fertilization on nonhuman primate oocytes, such embryos will be cultured either in vitro or in vivo in the oviduct of a pseduopregnant rabbit. Control embryos will consist of in vivo fertilized and cultured embryos either from natural mating or artificial insemination of squirrel monkeys or after fertilization in the rabbit oviduct, using techniques developed in pilot studies in this laboratory. The effect of varying proportion of genital tract secretions, pH, osmolarity and other environmental conditions on embryo development from the 2, 4, 8, 16 cell stages, morullae and blastocysts will be studied to characterize the necessary conditions for optimal development and determine the developmental time scale to be compared with published values in humans and other nonhuman primates. Individual studies of primate embryos developed to the various stages mentioned above will be conducted to examine the basic metabolism of the preimplantation embryo relative to biochemical energy sources, oxygen requirement, and amino acid incorporation into protein. In all studies, previously developed and proven techniques for the production of mature oocytes, their laparoscopic recovery, and their fertilization in vitro will be used to maximize data output from the animals without their sacrifice. The end result of these studies will be a comprehensive determination of the basic developmental stages and metabolism of nonhuman primate preimplantation embryos and a greater knowledge of necessary culture conditions to study this development.